A typical microphone device is known which has a microphone unit distanced from the base, specifically, has a microphone unit at the tip of the rod support on the base. Examples of such a microphone device include headset microphones and goose-neck microphones.
A headset microphone has a flexible support pipe with a cable passing therethrough for electrical connection to the microphone unit. The flexible pipe in the headset microphone is made thin (has a small inner diameter) not to draw much attention. A thick cable, which is difficult to pass through the flexible pipe, is connected to the thin cable at or around the inlet of the flexible pipe.
Condenser microphones, which are typically used as microphone units in headset microphones, suffer from audible noise caused by RF current flowing through impedance converters in the condenser microphones. To prevent such noise, the audio signal wires in the microphone are protected (shielded) from static damage. Unfortunately, the junction between the thick and thin cables at or around the inlet of the flexible pipe cannot be adequately shielded.
For example, Japanese Unexamined Patent Application Publication No. 2006-033216 (hereinafter referred to as “the patent literature”) discloses a condenser microphone in which the inner surface of a metal pipe is in contact with an exposed shield-covered cable in the pipe for the microphone. The shield-covered cable in the technique in the patent literature is a braided cable consisting of core wires and a copper braid therearound.
Even in the technique in the patent literature, a cable cannot be passed through a pipe with a small inner diameter and adequate shielding is not achieved due to a gap between the inner wall of the pipe and the low-density shielded wire.